| [Visitor (120.204.*.*)]answers [Chinese ] | Time :2021-09-22 |  Coronavirus particles are irregularly shaped, about 60-220nm in diameter. Virus particles outsource fat membranes, membranes
There are three glycoproteins on the surface: s, SpikeProtein, which is the receptor binding site, soluble cell action, and primary antigen site; New virus bud release and the formation of virus outsourcing membranes). A few species also include hemagglutinin (HE protein, Haemaglutinin-esterase). The nucleic acids of the coronavirus are non-sectional single-stranded RNA, long 2 7-31kd, the longest RNA nucleic acid chain in an RNA virus, has important structural characteristics specific to positive-chain RNA: namely, RNA chain 5' end has methylation "hat" and 3' end has PolyA "tail" structure.This structure is very similar to eukaryotic mRNA and is an important structural basis for the translation template of RNA itself, eliminating the transcription process of RNA-DNA-RNA. The rate of recombination between RNA and RNA of coronaviruses is very high, and the mutation of viruses is due to this high rate of recombination. After recombination, the RNA sequence changes, so does the amino acid sequence encoded by nucleic acids, and the proteins made up of amino acids change to change their antigen properties. The result of the change of antigen is that the original vaccine fails and the immune failure...
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In the mature particles of the coronavirus, there is no RNA polymerase (ViralRNApolymerase) required for RNA virus replication, which enters the host cell and expresses the viral RNA polymerase directly using viral genomic RNA as a translation template. This enzyme is used to transcribe the negative chain subgenomic RNA, the synthesis of various structural proteins mRNA, and the replication of viral genomic RNA. The maturation of mRNA of various structural proteins of coronaviruses, without the modified shearing process after transcription, is obtained directly through RNA polymerases and some transcription factors, in a mechanism of "discontinuous transcription", by identifying a specific transcription regulation sequence (TSR), selectively from the negative chain RNA, one-time transcription is formed into all components of a mature mRNA.After the replication of structural proteins and genomic RNA is complete, new coronavirus particles are assembled at the host cell's endoplasmic mesh and secreted out of the cell by the gorkye to complete its life cycle... |
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